Fusion splicing devices have been well known for some time and many of these devices are commercially available. One such device is described by the applicant in U.S. Pat. No. 5,002,351 issued Mar. 26, 1991 entitled Splicer for Optical Fibers. This and other similar devices are equipped with costly, permanent, tungsten electrodes capable of withstanding many repeated uses. The teachings of this patent and the following related art are incorporated herein by reference where applicable.
Another such device is described in U.S. Pat. No. 5,146,527 in the name of Mallinson issued Sep. 8, 1992. Mallinson's fusion splicer is designed to receive a consumable ferrule, having a bore through a central longitudinal axis, for accommodating two fiber ends for fusion within. A slot is formed in the ferrule into which permanent electrodes are temporarily inserted for fusing optical fibers positioned within the bore. Although the devices described in both of these patents appear to adequately perform their intended function, it is an object of this invention to provide a fusion block, having electrodes that are integral with the block and that are inexpensive and are designed to be used one or more times. Such a block should provide a clean fusion cavity in which fusion may take place. After fusion takes place, the block preferably remains with the spliced fused fibers.
U.S. Pat. No. 4,598,974 issued Jul. 8, 1986 in the name of Munn et al. describes an optical fiber connector having integral electrodes. Although Munn's device relates specifically to a connector having a pre-inserted optical fiber stub, it is possible to adapt this design to a fusion sleeve for fusing two unconnected optical fibers. However, it is believed that a limitation of Munn's connector is the cost related to assembling such sleeves that must be kept free of dust, debris and grease. In addition to these restrictions, it is difficult to mass produce such sleeves because each electrode must be individually inserted into its respective opening in the sleeve, adding to the cost of assembly.
Another more recently issued U.S. Pat. No. 5,222,171 issued Jun. 22, 1993 in the name of Straus, describes a sleeve similar to Munn's having integral electrodes and axial alignment means. In one embodiment shown in FIG. 10 of the Straus patent two pieces of metal are attached by an adhesive and act as electrodes on either side of tubular member. Each piece of metal has a hole and a transverse hole is formed in the tubular member. Application of electric current produces an arc from the edges of the holes, which fuse fiber ends therebetween. Although the Straus sleeve may work as described, placement of the electrodes in this manner, so that they are essentially parallel to one another on either side of the member, is not a preferred design and is costly to manufacture.
Therefore, it is also an object of the invention, to provide a consumable fusion block including electrodes that may be mass produced at a very lost cost.
It is also an object of the invention to provide a laminated fusion block having integral electrodes.
It is a further object of the invention to provide a fusion block having an electrode layer over or embedded in a non-conducting substrate.